Electronic timing and cutting apparatus



Oct. 12, 1965 c. D. BENNETT 3,211,036

ELECTRONIC TIMING AND CUTTING APPARATUS Filed NOV. 5, 1962 5Sheets-Sheet 1 CUTTER UPON COMPLETION OF CUTTING 51,, POSITION AT END\OF/0 SECONDS D ,9, 3D w @751 SW [/20 6 i 3 I 3 5w RESET RELAY 0 SRELAYRELAY I 234 235 228 I 202 208 2/6 I 2/8 r200 I l 220 I OUTPUT j i JRELAY A 2/0 205 I I T cur OF 33 INVENTOR.

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ELECTRONIC TIMING AND CUTTING APPARATUS 5 Sheets-Sheet 2 Filed Nov. 5,1962 .EDUutU Q3930 Oh INVENTOR. C. DENVER BENNETT Y B mQ x v8 2 -w: v IA m2 WQ ||/N\ ON\|\ N9 #9 m2 1 a m8 m8 w: o: @Q m: tauEu Eta E 53mm alumGwwm Q ATTORNEYS Oct. 12, 1965 c. D. BENNETT ELECTRONIC TIMING ANDCUTTING APPARATUS 5 Sheets-Sheet 3 Filed Nov. 5, 1962 k SumG Eta 3 E335QESU E INVENTOR. C. DENVER BENNETT BY t7 t7 ATi/QNE? NNm ONm Oct. 12,1965 c. D. BENNETT ELECTRONIC TIMING AND CUTTING APPARATUS 5Sheets-Sheet 4 Filed Nov. 5, 1962 FHDUN: U f NWMEFD U 8 I I i l l 1 B 5m U H 1mm @QHW 1 NJ Q? u m u u dNw MKQQQ wjw wow $04 Omd Q K EA a wmavwm v 03v 3% Pmmmm 33mm b. wwuv Q a m Rfikmumo L OH O H W INVENTORC.DENVER BENNETT BY 'EAY ARXDFAY ATTORNEYS Oct. 12, 1965 c. D. BENNETTELECTRONIC TIMING AND CUTTING APPARATUS 5 Sheets-Sheet 5 Filed Nov. 5,1962 FIG. 11.

D SWlTCH OPERATES A'l EITHER D1 ,D2 RD3 IN THIS GRAPH OUTPUT RELAYOPERATES 0N ZERO VOI7TAGE, LINE S SWITCH OPERATES AT 0 VOLTAGE 4 0 TIME8 9 1011121314151617181920 TIME IN $ECONDS FIG.12.

ZERO VO]./'IAGE LINE 4 5 6 '7 8 9I01]12.1311415161716192Dl TIME INSECONDS INVENTOR C.DENVER BENNETT BY FAY AND FAY ATTORNEYS United StatesPatent 3,211,036 ELECTRONIC TIMING AND CUTTING APPARATUS Charles DenverBennett, 485 Maplewood Ave., Struthers, Ohio Filed Nov. 5, 1962, Ser.No. 235,567 6 Claims. (Cl. 83210) This invention relates to an apparatusfor and method of measuring and dividing lengths of longitudinallymoving members, such as pipes, rods, sheets, extrusions, and the like,into predetermined fractional lengths, such as halves or thirds, or intopredetermined fixed lengths, as desired, or for cropping predeterminedlengths from the ends of such members, and to electronic timing circuitsuseful for accomplishing the purposes just described. This applicationis a continuation-in-part of my prior pending application Serial No.160,216, filed December 18, 1961.

In the metal processing industry there is a great need for apparatus forsubdividing lengths of longitudinally moving materials such as pipes,rods, and the like into predetermined fractional lengths or intopredetermined fixed lengths. However, the apparatus which has beenprovided in accordance with the prior art for accomplishing this purposehas been unsatisfactory in many respects. Thus, for example, the priorart apparatus generally has been very complicated, involving the use ofgreat numbers of electronic tubes and relays which necessitated largefinancial outlays for their initial installation and which alsopresented many maintenance problems. The prior art apparatus has alsobeen functionally inadequate in some respects, as, for example, beingincapable of recognizing a pipe length which is too short to be cut intofractions such as halves and instead cutting such pipe into two equalpieces each of which is too short and can be used only as scrap.Furthermore, the complexities of the prior art apparatus generally havebeen such that only highly skilled electronic technicians are capable ofeffecting the necessary repairs when a breakdown occurs on suchapparatus.

It is also frequently necessary in the metal processing industry to croppredetermined lengths from the ends of longitudinally moving materialssuch as pipes, rods, and the like, for various reasons, as, for example,because of off-gauge, rough, or irregular ends on the moving members.

Accordingly, it is an object of this invention to provide an apparatusfor and method of cutting lengths of longitudinally moving objects, suchas pipes, rods, sheets, and the like, into predetermined fractionallengths or into predetermined fixed lengths, with the apparatus beingsuch as to require only low first cost and little maintenance.

It is another object of this invention to provide an apparatus forcutting pipes, rods, and the like, which is relatively uncomplicatedcompared to the prior art apparatus for this purpose and which has fewerparts than the prior art apparatus.

It is another object of this invention to provide an apparatus forsubdividing pipes, rods, and the like, which includes electroniccircuitry which is relatively simple compared to prior art apparatus foraccomplishing this purpose, and which includes relatively simplecontrols for adjusting the apparatus for varying operating conditions.

Still another object of the invention is to provide an apparatus forsubdividing pipes, rods, and the like, which is reliable and eflicientin its operation and which is capable -of sensing when the rod or pipeis too short to be subdivided thereby to insure that at least one usablelength is produced from a pipe which is too short for subdivision,rather than a plurality of fractional lengths, none of which is equal tothe minimum length required.

It is another object of the invention to provide an apparatus and methodwhich can be used either for cutting longitudinally moving lengths ofpipes, rods, sheets, and the like into predetermined fractional lengthsor into repeating fixed lengths as desired.

Still another object of the invention is to provide an apparatus of thetype hereinabove described which operates with a high degree of accuracyin cutting the pipes or the like into fractional lengths or into fixedlengths.

Still another object of the invention is to provide an apparatus of thetype hereinabove described in which the pipe or the like can be cut intopredetermined fractional lengths or into predetermined fixed lengthsregardless of whether the pipe travels at a constant speed or at avariable speed.

Still another object of the invention is to provide an apparatus andassociated electronic circuitry for cropping predetermined lengths fromthe ends of longitudinally moving material to eliminate off-gauge,rough, or irregular ends.

In achievement of these objectives, there is provided in accordance withthis invention an apparatus for and method of measuring and dividinglengths of longitudinally moving material such as pipes and the likeinto either predetermined fractional lengths or predetermined fixedlengths. The apparatus includes a timing circuit having a capacitorwhich is charged through a current limiting impedance to thepredetermined trigger voltage of a gaseous discharge thyratron tube orother equivalent electronic control device to cause the thyratron tubeto fire and actuate a cutting and clamping device at the moment when themidpoint or other predetermined point of the longitudinally movingmaterial arrives at the cutter. Suitable sensing devices, preferablyproximity switches, are positioned adjacent the path of movement of thematerial being cut to cause the timing capacitor to begin charging whenthe leading end of the material being cut reaches the cutting device,and also to control the rate of charging of the timing capacitor as afunction of the length of the material to compensate for variations inlength of material being cut from a predetermined minimum length.

The timing apparatus of the invention also may be used for cuttingpredetermined fixed lengths of moving material, rather thanpredetermined fractional lengths, if desired. The timing device may beused also for other types of measuring or timing operations and is notre stricted to use in apparatus for cutting moving material.

Another embodiment of the invention is provided for croppingpredetermined lengths from the ends of the moving material, such aspipes or the like. The moving member which is to be cropped actuates afirst sensing switch to produce a first signal when the forward end ofthe material reaches a predetermined point along the path of movement,and act-uates a second sensing switch to produce a second signal whenthe forward end reaches a second predetermined point further along thepath of movement of the material. The first signal produced by themoving member initiates a capacitor charging operation, while the secondsignal initiates a capacitor discharging operation. In accordance withthe invention, separate charging and discharging circuits are providedfor the storage capacitor in such manner that the rate of discharge canbe varied relative to the rate of charging of the capacitor to therebycontrol the interval required for the capacitor to discharge to the samepotential level as that at which the charging operation began. Thisadjustable relation of the discharge rate to the charging rate of thecapacitor is utilized to determine the time lapse before the actuationof a control means such as a v thyratron gaseous discharge tube whichcontrols the cropping of the moving member. With the charging anddischarging rates of the capacitor being adjusted to have apredetermined ratio to each other, the length of material cropped fromeach piece of moving material remains the same regardless of the speedof the moving material as long as the speed of the moving materialremains constant.

Throughout the specification, the material which is being subdividedwill be referred to as a pipe for simplicity in description. However, itwill be understood that the term pipe is used as representative of anymoving material which is to be cut, such as pipes, rods, sheets,extrusions, or the like.

Further objects and advantages of the invention will become apparentfrom the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a schematic view showing the apparatus of the inventionemployed for cutting longitudinally moving pipe into predeterminedfractional lengths or into predetermined fixed lengths;

FIG. 2 is a simplified schematic diagram illustrating the timing deviceof the invention used for controlling the cutting into two equal lengthsof a longitudinally moving pipe or the like which moves at a constantspeed;

FIG. 3 is a schematic view showing the relation of the pipe which is tobe cut into two equal lengths to the S and D control switches when thepipe to be cut is just equal in length to the minimum length of pipe tobe cut for the given setting of the S and D switches;

FIG. 4 is a schematic view showing the relation of the pipe to be cut tothe S and D switches when the pipe length before cutting exceeds theminimum length of pipe to be cut for the given setting of the S and Dswitches;

FIG. 5 is a complete schematic diagram of the timing circuit of theinvention used for controlling the cutting into two equal lengths of alongitudinally moving pipe or the like which moves at a constant speed,the simplified schematic diagram of which was shown in FIG. 2;

FIG. 6 is a simplified circuit diagram of a timing circuit used forsubdividing a longitudinally moving pipe or the like into three equallengths where the pipe moves at a constant speed;

'FIG. 7 is a schematic view showing the relation of the pipe to be cutto the S switch and to the /2D and %D switches when the pipe which is tobe cut into three equal lengths is just equal in length to the minimumlength of pipe to be cut for the given setting of the S and /zD and %Dswitches;

FIG. 8 is a complete schematic diagram of the timing circuit used forcontrolling the cutting into two equal lengths of a pipe which is movingat a variable speed;

FIG. 9 is a schematic diagram showing the relation of the pipe to becropped to the A and B switches and t0 the cutter member;

FIG. 10 is a schematic diagram of the timing circuit used forcontrolling the cropping of predetermined lengths from the ends oflongitudinally moving pipe or the like which moves at a constant speed;

FIG. 11 is a graph which compares the charging rate with the dischargingrate of the storage capacitor when the constant of the timing circuit isone; and

FIG. 12 is a graph which compares the charging rate with the dischargingrate of the storage capacitor when the constant of the timing circuit isone-half.

Referring now to FIG. 1 which shows schematically the orientation of thevarious parts of the apparatus relative to the longitudinally movingpipe P which is being cut, there are shown a plurality of longitudinallyspaced pedestals or other suitable conveyor supports generally indicatedat 10, 12, 14, and 16 on which are mounted conveyor rolls 18, 20, and22. Certain of the conveyor rolls, such as rolls 20 and 22 at oppositeends of the roll conveyor structure, are driven by power drive meanssuch as the motor-driven drive shafts 24 and 26, respectively.

A length of pipe P is supported for movement along the plurality ofrolls 18, 20, 22, the rolls being V-shaped or otherwise suitably shapedto receive the pipe being transferred. A cutter 28 is suitably supportedin overlying relation to the moving pipe at a point midway betweenpedestals 12 and 14. Clamp members 30 are positioned on either side ofthe pedestals 12 and 14 in position to clamp the pipe and stop themotion thereof when the cutter 28 is energized to cut the pipe at thepredetermined fractional length or predetermined fixed length as will beexplained hereinafter.

In order to control the clamping and cutting operation when apredetermined fractional length or a predetermined fixed length haspassed by the cutter 28, a pair of sensing switches S and D areprovided. When the pipe is to be cut into two equal lengths, the S and Dswitches are spaced apart a distance corresponding to the minimum lengthbefore cutting of the pipe which is to be cut. Thus, for example, if a-foot length of pipe is the minimum length of pipe to be cut, the S andD switches are spaced apart 100 feet along the path of movement of thepipe. The S switch is positioned at the same position as the cutteralong the path of travel of the pipe, while the D switch is displacedfrom the S switch in the direction of the trailing end of the pipe by adistance equal to the length before cutting of the minimum length ofpipe to be cut. The spacing between the S and D switches varies fordifferent fractional cuts and the explanation just given of thepositions of the S and D switches applies only where the pipe is to becut into two equal lengths.

The S and D switches are preferably switches of the proximity type whichdo not require actual contact with the moving material. Proximityswitches are well known in the art and may operate either on theinductive or capacitative principle. The use of proximity switches forthis purpose is preferred due to the fact that it avoids wear on theswitches. However, switches of the type which actually are in contactwith the moving pipe may be used if preferred.

The S switch is actuated at the instant that the leading end of the pipepasses by it, closure of the S switch energizing the S relay andoperating the normally closed contact 8' to open position to start acapacitor charging operation, the length of time required to charge thecapacitor determining the time of firing of a thyratron gas tube whichcontrols the pipe elements and cutting operations.

The D switch is actuated by the presence of a pipe adjacent thereto, thelength of time that the D switch is actuated after the initial actuationof the S switch by the leading end of the pipe being a measure of thelength of the pipe in excess of the minimum pipe length for which the Sand D switches are set. Actuation of the D switch by the presence of apipe actuates the D relay to open the normally closed D contact which isconnected in shunting relation to limiting resistance in the capacitorcharging circuit, the D contact continuing to remain open as long as thepipe continues to pass by the D switch. The opening of the shunting Dcontact by actuation of the D switch increases the time required tocharge the capacitor which controls the time of firing of the thyratroncontrol tube, thereby increasing the time interval before actuation ofthe pipe clamping and cutting devices, as will be described hereinafter.

Referring now to FIG. 2 of the drawings, there is shown a simpleschematic diagram illustrating the principle of the timing and controlcircuit used for subdividing a longitudinally moving pipe or the likeinto two equal lengths. The timing circuit includes a gaseous dischargetube of the thyratron type, preferably a 2D21W thyratron generallyindicated at 40, including anode 42, cathode 44, a control grid 46, andalso a screen grid 48, which is connected to cathode 44. The operatingcoil 52 of a relay generally indicated at 50 is connected in the outputcircuit of anode 42. Relay 50 includes two normally open contacts 53 and54 which are actuated to closed position by energization of relayoperating coil 52 due to current flow in the circuit of anode 42 whenthe thyratron tube 40 fires. Contacts 53 and 54 are respectively in thecircuits of solenoids 56 and 57. Closure of contact 53 is efiective toenergize solenoid 56 to actuate clamps 30 to a position in which thepipe P is clamped against movement to permit cutting of the pipe.Closure of contact 54 is effective to energize solenoid 57 to actuatecutter 58 to cut the pipe.

Since it is a characteristic of gaseous discharge thyratron tubes thatonce firing of the tube has occurred the control grid loses control, itis necessary to open the anode circuit to cause the tube to revert to anopen circuit condition in which the control grid again has control. Toopen the anode circuit as just described and thus reset the tube for thenext cutting operation, a reset relay generally indicated at 60 isprovided. Reset relay includes an operating coil 61 which controls anormally closed contact 62 in the anode circuit of tube 40. Operatingcoil 61 of reset relay 60 is energized by closure of' contact 64 uponthe completion of the pipe cutting operation, contact 64 being actuatedto closed position by movement of cutter 58 to a position indicative ofcompletion of the cutting operation. Energization of the operating coil61 of reset relay 60 opens normally closed contact 62 in the anodecircuit of tube 40 thereby to reset the tube for another cycle ofoperation.

It is a well-known characteristic of thyratron gaseous discharge tubesthat a certain predetermined anode potential the tube will fire orbecome conductive when a predetermined trigger voltage is applied to thecontrol grid of the tube. In the timing circuit of FIG. 2, the timerequired for the thyratron tube 40 to reach the trigger voltage iscontrolled through a resistance-capacitance timing circuit including acapacitor 66 connected between grid 46 and cathode 44. Capacitor 66 isconnected across a constant voltage regulated D.C. supply at terminals68 and 70 in series with a limiting resistor generally indicated at 72,including two equal series-connected resistance sections 73 and 74. Inaccordance with an impor tant feature of the invention, the contacts 8'and D previously referred to are connected in the timing in a mannerwhich will now be described.

The S contact is placed in parallel with capacitor 66 so that thecharging of the capacitor through resistors 73 and 74 does not beginuntil the S switch adjacent the path of movement of the pipe has beenactuated by the passage adjacent thereto of the pipe which is to be cutto cause the S relay to move contact S from its normally closed positionto open position. Opening of the S contact removes the short circuitshunt path which had existed across capacitor 66 when contact S wasclosed, and permits capacitor 66 to begin charging. The D switch which,in the embodiment of FIGS. 25 is mounted a distance from the S switchequal to the minimum length of pipe which is to be cut, or a distanceequal to twice the length of the out which is to be made, actuates the Drelay to open the normally closed D contact when pipe is passingadjacent the D switch. The D contact is connected in parallel orshunting relation with the resistance section 74, which, as previouslystated, is identically equal in resistance value to resistance section73 and thus equal to exactly one-half the total resistance 72. Thus,when the D switch is actuated due to the presence of pipe passingadjacent thereto, normally closed contact D is opened by the D relay,and both resistance sections 73 and 74 are connected in series relationwith capacitor 66. On the other hand, if no pipe is adjacent the Dswitch, the D relay is deenergized to permit reclosing of the normallyclosed D contact.

If the circuit constants are so adjusted, for example, that it takesseconds for the capacitor 66 to charge up to the trigger voltage on tube40, when contact D' is closed 6 and only half the limiting resistance 72is in series with capacitor 66 then it would take 20 seconds to build upto the same trigger voltage if switch contact D is open and both of theequal resistance sections 73 and 74 were in series with capacitor 66 forthe entire charging period. Similarly, for any portion of the chargingperiod of capacitor 66 during which contact D is closed, the chargingrate of capacitor 66 will be twice as great as during the portions ofthe charging period when contact D is open.

In accordance with the invention, the relationship of the opening andclosing of contact D' to the total time required to charge capacitor 66to the trigger voltage of tube is used to measure the length of a pipeor the like which is to be cut and to so control the charging period ofcapacitor 66 as to cause the trigger voltage on grid 46 of the tube 40to be reached after an interval such that the clamping and cuttingaction will occur precisely when the midpoint of the pipe reaches thecutter, thereby to cut eachpipe into two equal lengths. The timing andcontrol circuit of FIG. 2 operates to cut the pipe into two equallengths as long as the length of the pipe is between the minimum lengthfor which the S and D switches are set, at one extreme, and twice theminimum length at the other extreme. Thus, for example, if the S and Dswitches are set for a minimum pipe length before cutting of 100 feet,the timing and control circuit will cut the pipe into two equal lengthsas long as the pipe length before cutting is in the range 100 feet-200feet.

Several specific examples of the operation of the timing circuit of FIG.2 now will be described. Assume first that a pipe exactly 100 feet inlength is to be cut in half. As will be seen from FIG. 3, the 100-footpipe exactly spans the length between the S switch adjacent the leadingend of the pipe and the D switch adjacent the trailing end of the pipe.Assume that the pipe travels longitudinally on the rolls 18, 20, and 22at a constant speed of 5 feet per second. Assume that the value of thelimiting resistors 73 and 74 has been adjusted so that with bothresistor sections 73 and 74 connected in series with capacitor 66 forthe entire charging period, the time required to charge capacitor 66 tothe trigger voltage of tube 40 is 20 seconds whereas only 10 seconds isrequired to charge capacitor 66 to the trigger voltage of tube 40 ifonly resistor section 73 is in series with capacitor 66 for the entirecharging period of capacitor 66. The minimum length of pipe to be cutand the rate of movement of the pipe are factors in selecting theresistance and capacitance values which control the charg ing timerequired to reach the trigger voltage on the thyratron tube.

As soon as the leading end of the -foot pipe P in FIG. 3 reaches the Sswitch, switch S actuates the S relay to open contact S to permitcapacitor 66 to begin charging through the limiting resistance. Since atthe same instant that the leading end of pipe P reaches switch S, thetrailing end of the pipe is just passing out of contact with switch D atthe trailing end of the pipe, contact D controlled by relay D is closedand shunts out resistor section 74. Resistor 73 and capacitor 66 havetheir values so related that when the charging circuit is only throughresistor 73 for the entire charging period, capacitor 66 will be chargedto the trigger voltage of tube 40 in 10 seconds. During this lO-secondperiod, which begins when the leading end of pipe P actuates switchS,the pipe will move 50 feet beyond the S switch and beyond the cutter,since the rate of movement of the pipe is 5 feet per second. Thus, atthe end of the ten-second interval required to charge capacitor 66 withonly resistor 73 in circuit, tube 40 will fire and current conduction inthe circuit of anode 42 will energize operating coil 52 of output relay50. Energization of coil 52 will close normally open relay contacts 53and 54 which are respectively in the electrical circuit of the clamps 30and cutter 58 to energize elements, such as solenoids 56 and 57,

in the respective electrical circuits of clamps 30 and cutter 58. Theenergization of the electrical circuits of the clamps and cutter causesthe clamps to clamp the moving pipe against movement and causes thecutter to cut the pipe in two equal lengths. Upon completion of thecutting operation, contact 64 is closed by cutter 58 to energizeoperating coil 61 of reset relay 60. Energization of reset relay coil 61opens normally closed contact 62 in the circuit of anode 42 thereby toreestablish control of the tube 40 by grid 48 to reset the timingcircuit for the next timing operation.

Now, assume that a pipe 110 feet long is to be cut rather than the100-foot pipe previously described. Assume, as before, that the pipe ismoving at a constant rate of speed of feet per second. In this case,when the leading end of the pipe causes the opening of the S contact tobegin charging of capacitor 66, the trailing end of the pipe stillextends feet rearwardly of the D switch. Hence, since the rate ofmovement of the pipe is 5 feet per second, it will take the trailing endof the pipe 2 seconds to reach the D switch. During the 2 seconds thatthe trailing end of the pipe is moving to reach the D switch, the D'contact is maintained open by the D relay controlled by the D switch.With the D contact open, both of the equal resistor sections 73 and 74are in series with the capacitor 66 for a period of 2 seconds. Hence,during this 2-second interval capacitor 66 is charging at one-half therate that it would if only the resistor 73 were in series therewith.

It can be shown that the total time required to charge capacitor 66 tothe trigger voltage of the thyratron tube can be calculated according tothe following formula:

where T, is the actual total charging time required to reach the triggervoltage of the thyratron tube 40 T is the time during the chargingperiod during which both the equal resistor sections 73 and 74 areconnected in the charging circuit of capacitor 66 T is the charging timerequired to reach the trigger voltage of tube 40 if both resistorsections 73 and 74 were in the charging circuit for the entire chargingperiod.

Since in the assumed example, the pipe to be cut is 110 feet in length,T the time during the charging period during which both resistors 73 and74 are connected in the charging circuit, is 2 seconds, since 2 secondsare required for the 10 feet of the pipe which projects beyond the Dswitch to pass the D switch, during which 2-second period the D switchremains open to cause both resistors 73 and 74 to be connected in thecharging circuit of capacitor 66. T is assumed to be seconds in theassumed example.

Substituting the values just given into the equation:

Therefore, solution of the equation indicates that 11 seconds chargingtime is required to charge the capacitor 66 to the trigger voltage oftube 40, at the end of which interval tube 40 becomes conducting toenergize output relay 50 to actuate clamps and cutter 58. Since bydefinition the pipe is moving at the rate of 5 feet per second, the pipewould have moved 55 feet beyond the S switch at the time the thyratrontube fired, which would be the exact midpoint of the 110-foot length ofthe pipe. Thus it can be seen that the timing circuit automaticallycomputes the length of the pipe and causes the actuation of the clampingand cutting devices at the time the exact midpoint of the pipe reachesthe cutter.

Reference now is made to FIG. 5 which shows a complete schematic of thecircuit used for dividing pipe lengths and the like into two equallengths. The power supply for the timer circuit is derived from analternating current input supply which may have, for example, a voltagerating of 117 volts. The input voltage is applied to the primary winding102 of a transformer generally indicated at 100. The voltage oftransformer secondary winding 104 is applied across a voltage doublingcircuit including capacitors 106 and 108 and silicon diode rectifiers110 and 112. The DC. output voltage of the voltage doubling circuit isderived at terminals 114 and 116 and is applied to a voltage regulatingcircuit including a limiting resistor 118 and a plurality ofseries-connected neon bulbs generally indicated at 120 which maintain aconstant output voltage across their terminals. The timing capacitor 126which is to be charged is connected across the output terminals 122 and124 of the neon voltage regulator tubes 120 in series with four currentlimiting resistors 128, 130, 132, and 134. Adjusting taps 136 areprovided for the resistors and 132 to provide adjustment of theresistance values when required.

The normally closed D contact is connected in shunting relation toresistors 132 and 134 which are of equal magnitude to the resistors 128and 130, so that when the D contact is in its normally closed positiononly one-half of the total resistance value of resistors 128-130-132-134is included in series with capacitor 126.

The normally closed S contact is connected in parallel shunting relationto timing capacitor 126 so that when the S contact is in normally closedposition, timing capacitor does not charge.

The thyratron gas tube includes an anode 142, a cathode 144, and acontrol grid 146. Control grid 146 is connected to one terminal ofcapacitor 126 in series with a neon bulb 148 which conducts only when apredetermined voltage, such as 60 volts, is applied across itsterminals. A bias voltage is supplied to control grid 146 from secondarywinding 152 of a transformer 150, the primary winding 151 of transformerbeing con nected to the secondary winding 105 of supply transformer 100.The biasing voltage supply circuit for grid 146 includes a voltagedoubling circuit having capacitors 154 and 156 and diode rectifiers 158and 160 connected across the secondary winding 152 of transformer 150. Avoltage regulating neon bulb 162 is connected across the outputterminals of the voltage divider in series with a current limitingresistor 164. Neon bulb 162 provides a stable DC. voltage output whichis applied in series with resistors 166 and 168 across bias resistors170 and 172 which control the bias voltage of control grid 146.

Current conduction occurs through neon bulb 148 only when the voltageacross bulb 148 builds up to a certain value, such as 60 volts. Theinstant that neon bulb 148 becomes conductive, a positive pulse isapplied to the grid 146 of thyratron tube 140 to cause the tube to firethereby to energize output relay 190. If the voltage across theresistors 170 and 172 is adjusted, for example, to 30 volts, the voltageacross the capacitor 126 need build up to only 30 volts because thevoltages across timing capacitor 126 and across resistors 170 and 172are in series across neon bulb 148. Thus, if the voltage acrossresistors 170 and 172 is 30 volts, then 30 volts voltage drop acrosscapacitor 126 is sufficient to discharge neon tube 148 to apply apositive pulse to grid 146 to cause firing of tube 140.

The anode 142 of tube 140 derives its DC. voltage supply from a voltagedoubler circuit supplied from secondary winding 178 of transformer 150,the voltage doubled circuit including capacitors 180, 182, and dioderectifiers 184 and 186.

The operation of the circuit in accordance with the complete schematicdiagram of FIG. 5 is substantially like that described in connectionwith the simple schematic diagram of FIG. 2. When the leading end of thepipe to be cut moves adjacent the S switch, the S relay is actuated tocause normally closed contact S to open to permit capacitor 126 to startcharging. The rate of charging of capacitor 126 depends upon whether ornot the D' contact, which is in shunt with resistor sections 132 and134, is open or closed, as previously explained. This, in turn, dependsupon how much of the length of the pipe to be cut projects beyond the Dswitch, all as previously explained. When the voltage on capacitor 126reaches a value such that this voltage plus the voltage across biasingresistors 170 and 172 is sufiicient to cause conduction through neonbulb 148, neon bulb 148 fires and thus applies a positive pulse to thecontrol grid 146 of the thyratron tube 140. Upon firing of tube 140, theoutput relay 190 in the circuit of anode 142 is energized thereby toactuate contacts in the cutter control circuit and in the clamp controlcircuit to cause clamps 30 to clamp the pipe and to cause the cutter tocut the pipe at its midpoint. Upon completion of the cutting operation,the reset relay circuit is energized to open normally closed contact 192in the anode circuit of tube 140 thereby to reset the tube for anothercycle of operation.

While the timing circuit and the position of the S and D switches shownin the embodiment of FIG. have been arranged to control cutting of thepipes or other moving material into two equal lengths, the timingcircuit and the position sensing switches also may be arranged to causesome other fraction of the total length of the pipe to be cut ifdesired. FIGS. 6 and 7 show the circuit of the timing device and thelocation of the position sensing switches used when the pipe or othermoving material is to be cut into three equal lengths. In using thetiming circuit of FIG. 6 to out a pipe into three equal lengths, themaximum length of the pipe to be cut must not exceed 150 percent of theminimum length of the pipe to be cut.

In cutting the pipe or the like into three equal lengths, three switchesare used to sense the position of the pipe relative to the cutter,namely the S switch, the /2D switch, and the /sD switch. Each of theseswitches is connected in series with a relay, these relays beingrespectively indicated as the S relay, the /2D relay, and the /sD relay.The S switch is positioned at the same point along the path of movementof the pipe as the cutter, and is first actuated by the leading end ofthe pipe, as described in the previous embodiments. The /sD switch ispositioned a distance from the S switch equal to the length beforecutting of the shortest pipe which is to be cut. Thus, if a pipe havinga minimum length of 100 feet is to be cut into three equal lengths, the/3D switch is positioned 100 feet from the S switch in the direction ofthe trailing end of the pipe. The /2D switch is positioned a distancefrom the S switch equal to two-thirds the distance of the /2,D switchfrom the S switch or, in the example shown in FIG. 7, the /2D switch ispositioned a distance of 66 /3 feet from the S switch.

The /sD relay, operated by the /sD switch, controls a normally closedcontact 228 and a normally open contact 230, the connection of whichwill be explained hereinafter. The /2D switch controls the actuation ofa normally closed contact 234.

The timing circuit shown in FIG. 6 for timing the cutting of a pipe intothree equal lengths includes a thyratron gas tube generally indicated at200, including an anode 202, a cathode 204, and a control grid 206'. Anoutput relay 205 is connected in the circuit of anode 202 to operatecontacts in the electrical circuits of the clamps and cutter aspreviously described in connection with the embodiments of FIGS. 25. Areset contact 207 also is connected in the' circuit of anode 202 aspreviously explained. A capacitor 212 is connected between control grid206 and cathode 204, and a normally closed S switch is connected inparallel with capacitor 212. Four resistor sections 214-216-218-220,each of equal magnitude, are connected inseries with capacitor 212 10across the terminals 208 and 210 of a regulated constant D.C. voltagesupply.

As seen in FIG. 6, two shunt paths are provided in parallel with eachother across the two series-connected resistor sections 218220, thesetwo resistor sections comprising one-half of the total resistance ofresistor sections 214-216-218-220. The first of these shunt pathsincludes the normally closed contact 228 which is operated to openposition when the %D relay is energized by the presence of the pipeadjacent the /aD switch. Contact 228 is connected in series in the firstshunt path with a normally closed contact 236 which is actuated to openposition upon the energization of the output relay 205 in the circuit ofanode 202 of thyratron tube 200. The second shunt path across resistorsections 218220 includes the normally closed contact 234 which isactuated to open position when the /2D relay is energized by thepresence of the pipe adjacent the /zD switch.

A separate shunt path is provided across resistor section 220 bynormally open contact 230 which is operated to closed position when the/2.D relay is energized by the presence of the pipe adjacent the %Dswitch.

The timing circuit of FIG. 5 and the position sensing switches shown inFIG. 6 cooperate to effect the division of the pipe into three equallengths in two separate measuring and cutting operations, as follows:

(1) Measurement of the pipe to determine when /3 of the length thereofhas passed by the cutter, and actuation of the clamps and cutter to makea cut at a point corresponding to /3 of the length of the original pipe.

(2) Measurement of the length of the remaining /2, of the original pipelength and actuation of the clamps and cutter to make a cut at themidpoint of the remaining /3 of the pipe length, or, in effect, cuttingthe remaining /3 of the pipe length into two equal lengths. This portionof the cutting operation involves use of a timing circuit similar tothat used in the embodiment of FIGS. 2-5.

The shunt path connections across the limiting resistor 220 and acrossresistors 218220 established by the selective opening and closing of thevarious contacts 228- 230-234-236 permits the completion of the twosequential steps just described and provides what might be termed a dualratio timing device.

In explaining the operation of the circuit of FIG. 5, it will first beassumed that a pipe having a length greater than feet is to be cut intothree equal lengths, and that the pipe moves along the conveyor rolls ata constant rate of speed of 5 feet per second. It is also assumed thatthe position sensing switches are set for a minimum length of pipe,before cutting, of 100 feet, with the /aD switch being positioned 100feet from the S switch, and with the /2D switch being positioned 66 /3feet from the S switch and 33 /3 feet from the /2,D switch.

Cutting the first one-third of the pipe With the conditions as justassumed, when the leading end of the pipe has moved along the conveyorrolls to a point where it is opposite the S switch, the trailing end ofthe pipe is still at a point beyond the /2.D switch. When the leadingend of the pipe is adjacent the S switch, the S switch is actuated toenergize the S relay to open the S contact connected in parallel withcapacitor 212, thereby to permit charging of capacitor 212 to begin.Since, at the same time, the pipe also is moving adjacent the /2D switchand the /sD switch and extends beyond the /3D switch, both the /2Dswitch and the /3D switch are actuated to energize the /2D relay and the/aD relay. Energization of the /2D relay opens the normally closedcontact 234 to open one of the shunt paths across resistor sections 218and 220. Energization of the %D relay opens the normally closed contact228 to open the other shunt path across resistor sections 218220.Energization of the /3D relay also closes the normally open contact 230.Thus, both of the shunt paths across resistor sec tions 218 and 220 areopen, but the shunt path across resistor section 220 through contact 230is closed. Therefore, with both the /3D relay and the /2D relayenergized, the current flow to charge capacitor 212 is through limitingresistors 214-216-218.

After the pipe has moved beyond the /3D switch but is still in contactwith the /2D switch, and assuming that the charge on capacitor 212 hasnot reached the trigger voltage of the thyratron tube, the /3D switch isdeactivated to deenergize the /3D relay, thereby to open contact 230 andclose contact 228. Also, since the pipe by definition must be within thelength limits of 100-150 feet, assuming that the minimum length is 100feet in the example, the trailing end of the pipe will not reach the /2Dswitch before the first one-third cut is made. Therefore, during theentire interval before the first onethird cut is made, the /2D relayremains energized to maintain contact 234 open. Thus, when the trailingend of the pipe has passed the /3D switch but has not reached the /2Dswitch, and assuming that thyratron tube 200 has not fired, the shuntpath through contact 230 is open and the shunt path through contact 234is open. However, the shunt path through the series-connected contacts228-236 is closed, thereby causing resistor sections 218 and 220 to beshunted. Thus, the charging circuit to capacitor 212 under theseconditions is through resistor sections 214 and 216. This causes theratio of the charging current to capacitor 212 to be 1.5 times as greatas it was when the charging circuit was through resistor sections214-216-218.

To summarize, if the length of the pipe is greater than the minimumlength of pipe to be cut, and not greater than one and one-half timesthe minimum length, both of the following conditions may occur duringthe first one-third of the travel of the pipe:

(1) With the pipe adjacent both the /3D switch and the /2D switch, theAD relay and the /2D relay are both energized. With both of these relaysenergized, the only shunt path is through closed contact 230 whichshunts out resistor section 220, thereby causing the capacitor 212 to becharged through resist-or sections 214, 216, and 218.

(2) If the pipe has passed the %D switch, but is still in contact withthe /2D switch, and one-third of the length of the pipe has not yetpassed the S switch to cause firing of thyratron tube 200, only the /2Drelay will be energized. With this condition of the relays, contact 230of the /3D relay will be open and contact 228 of the /2 D relay will beclosed, and contact 234 of the /2D relay will be open. Therefore, theshunt path will be closed through contacts 236 and 228 across resistorsections 218 and 220. This causes capacitor 212 to be charged throughresistor sections 214 and 216, and the current flow through these tworesistor sections will have a ratio of 1.5 to 1 to the current flowwhich occurred through the three resistor sections 214, 216, and 218.Therefore, capacitor 212 will charge 1.5 times as fast during the periodof the first /3 cut when the pipe has passed out of contact with the /3Drelay as it did when the pipe was still passing adjacent the /3D relay.

When the capacitor 212 finally becomes charged to a potential sufficientto trigger the firing of thyratron tube 200, the current flows throughoutput relay 205 and closes contacts in the control circuits for theclamps and for the cutter to cause the pipe to be clamped and to causethe cutter to cut the pipe at one-third of its length. When the cuttingoperation is completed, the cutter closes a contact which energizes areset relay to open the reset contact 207 in the anode circuit of tube200, as previously explained in connection with the embodiment of FIGS.2-5. Also, the energization of the output relay 205 opens the contact236 in series with normally closed contact 228 of the %D relay. Theoperation of contact 236 is such that it does not revert to closedposition when thyratron tube 200 stops conducting, but instead must bereset to closed position by appropriate means when the next pipe is tobe cut.

Cutting the remaining 0f the pipe in half Upon the opening of resetcontact 207 at the completion of the cutting and clamping operation tocause deenergi- Zation of the thyratron tube, the cutter is retractedfrom cutting position and the clamps are released from clampingengagement with the pipe. The pipe which has now had one-third of itslength severed begins to move again. The circuit of FIG. 5 now providesa timing and control action which causes the remaining two-thirds of thepipe to be cut into two equal lengths, thus resulting in a severing ofthe original pipe into three equal lengths.

Since the /3D switch is open due to the fact that the pipe, being withinthe length limits previously specified and already having /3 of itslength severed therefrom, can no longer be adjacent the /3D switch, the%D relay is deactivated to close contact 228 and to open contact 230.However, if the original length of the pipe was greater than the minimumlength, the pipe after the first /3 cut still would be adjacent the /2Dswitch to continue actuation of the /2.D relay and to maintain contact234 open. With contacts 230, 234, and 236 all open as just described,all of the shunt paths across resistor sections 218 and 220 are open.

Thus, for the portion of the length of the remaining two-thirds of theoriginal pipe length which projects beyond the /2D switch, all fourresistors 214, 216, 218 and 220 are in the charging circuit of capacitor212. As soon, however, as the trailing end of the pipe passes the /2Dswitch, the /.zD relay is deenergized, causing the normally closedcontact 234 to reclose, thereby establishing a shunt circuit acrossresistor sections 218 and 220. With contact 234 closed, only resistorsections 214 and 216, which have a resistance equal to one-half thevalue of the total resistance 214-216-218-220, are in the chargingcircuit of capacitor 212, and the capacitor 212 therefore charges attwice the rate that it did when the shunt circuit through contact 234was open. When the capacitor 212 becomes charged to the trigger voltageof tube 200, the tube fires and energizes relay 205 to cause actuationof the clamps and of the cutting device as previously explained, therebyto effect the cutting of the remaining two-thirds of the length of thepipe into equal halves. Thus, by the use of the dual ratio timingcircuit hereinbefore described, the pipe first has one third of itslength cut off and then the remaining two-thirds of the length is cut inhalf.

There is shown in FIG. 8 a dividing timer circuit employed when thematerial to be cut advances at a variable speed and it is required todivide the material into predetermined fractional lengths. The variablespeed timing circuit operates generally in accordance with the sameprinciples as the constant speed timing devices hereinbefore described,but additionally has features which compensate for the variable speed ofthe moving material such as the pipe or the like. The circuit shown inFIG. 8 is intended to time the cutting of a pipe or the like into equalhalves and cooperates with S and D switches positioned as shown in FIGS.3 and 4.

The variable speed timer circuit derives its input power from analternating current power supply connected to the primary winding 302 ofthe transformer generally indicated at 300. The secondary winding 304 ofthe transformer 300 is connected to a voltage doubling circuit includingcapacitors 306 and 308 and diode rectifiers 310 and 312. The DC. outputof the voltage doubling circuit is applied to a voltage regulatorgenerally indicated at 314 formed by a plurality of series-connectedneon bulbs. The constant DC. voltage output of the voltage regulator 314is connected in series with load resistance 315 across the anode 317 andcathode 318 of a thyratron tube generally indicated at 316. Tube 316also includes a control grid 319. Connected in shunt relation to theanode-cathode circuit of thyratron tube 316 and in series 13 with dioderectifier 324 and choke coil 328 are two seriesconnected capacitors 320and 322 of equal capacitance value. The output end of the twoseries-connected capacitors 320 and 322 at the junction 327 with dioderectifiers 324 is connected through diode rectifiers 323 to timingcapacitor 325.

The S contact, operated by the S switch through the S relay is connectedin parallel shunt relation with capacitor 325 in the same manner asdescribed in the previous circuits, the S contact normally being closedto shunt out capacitor 325 to prevent charging thereof when the pipe tobe cut is not in proximity to the S switch, and being actuated to openposition to permit charging of the capacitor 325 when the pipe is inproximity to the S switch.

The variable speed timing circuit of FIG. 8 also includes a secondthyratron tube generally indicated at 328, including an anode 330, acathode 332, and a control 'grid 334. One end of timing capacitor 325 isconnected to control grid 334 through a neon bulb 336 which functions inthe same manner as described in connection with the circuit diagram ofFIG. to trigger the firing of the thyratron tube. The opposite end ofcapacitor 325 is connected to cathode 332 through a variable resistor338. The voltage supply for anode 330 and the biasing voltage supplycircuit for grid 334 are all substantially as described in theembodiment of FIG. 5 and will not be described again.

1 In accordance with the principle of operation of the circuit of thevariable speed timer of FIG. 8, the regulated constant DC. voltageacross the output of the voltage regulator tubes 314 is pulsed bythyratron tube 316 through the capacitors 320 and 322, and the pulsesare accumulated or added up on the capacitor 325 because of the blockingaction of silicon diode rectifiers 323 and 324 which are poled in suchmanner as to permit discharge of capacitor 325 only through neon bulb336 and thyratron tube 328 when neon bulb 336 and tube 328 fire. Dioderectifiers 323 are connected in series between the output end 327 of theseries-connected capacitors 320 and 322 and the terminal 329 of timingcapacitor 325.

. An auxiliary circuit generally indicated at 340 in FIG. 8 is providedto varythe number of pulses supplied by thyratron tube 316 in proportionto the linear speed of the material being divided. This auxiliarycircuit will now be described. The auxiliary circuit derives its powerfrom a secondary winding 342 on input power supply transformer 300.Secondary winding 342 supplies power through a transformer 344 to avoltage doubling circuit including condensers 346 and 348 and silicondiodes 350 and 352. The output voltage from the voltage doubling circuitis fed through a limiting resistor 353 to a voltage regulator includinga plurality of series-connected Zener diodes 354. The constant regulatedD.C. voltage supplied by Zener diodes 354 is connected across apotentiometer 356. A capacitor 358 has one of its ends connected throughresistors 364 and 365 to an adjustable tap on potentiometer 356, theopposite end of capacitor 358 being connected across the opposite end ofthe potentiometer. A neon bulb 370 is connected in series with theprimary winding 372 of a transformer whose secondary winding 374 isconnected in the input circuit of control grid 319 of thyratron tube318. The voltage across neon bulb 370 which is derived from the inputvoltage supply is adjusted principally by the adjustable tap ofpotentiometer 356 to provide a voltage across neon bulb 370 just belowits firing voltage. A small additional voltage is connected across theinput to neon bulb 360, preferably across the resistances 364-365, thisadditional voltage being derived from a pulse generator source having apulse frequency which is indicative of the linear speed of the movingpipe or rod. For example, a tachometer generator may be attached to anyone of the roll members 18, 20, 22 on which the pipe moves past thecutter, the tachometer generator being driven at a speed which isproportional to the rate of movement of the conveyor rolls and hence ofthe rate of movement of the pipe to be cut. The tachometer generator hasa voltage characteristic such that once in each cycle of its outputvoltage, a voltage peak is reached which is suflicient to cause firingof neon bulb 370. Each discharge of capacitor 358 through neon bulb 370provides a pulse of current through the primary winding 372 which istransferred to the secondary winding 374 in the input circuit of controlgrid 319 of thyratron tube 316. The frequency of these pulses is afunction of the rate of rotation of the tachometer generator and henceof the linear speed of the pipe or the like moving along the rollconveyor.

Each voltage pulse on secondary winding 374 reaches control grid 319 oftube 316 through capacitor 366 which is in series with secondary Winding374 in the input circuit to grid 319. This voltage pulse causes tube 316to fire, connecting the regulated D.C. voltage supply across loadresistor 315 and causing a discharge of capacitors 320 and 322 betweenthe anode and cathode of tube 316. Although tube 316 is a thyratrontube, the circuit constants are such that tube 316 does not continue tofire as a thyratron tube normally does because the current through it istoo small to maintain ignition, but instead tube 316 instantly revertsback to open circuit condition once capacitors 320 and 322 havedischarged therethrough. Tube 316 is maintained in open circuitcondition by the bias voltage across resistor 368 until another pulsefrom secondary winding 374 causes tube 316 to fire again.

Each time that tube 316 reverts to its open circuit connection at theend of each pulse from secondary winding 374, it applies a voltageacross the discharged capacitors 320 and 322 through diode rectifiers324, causing capacitors 320 and 322 to recharge. Each time a pulse ofcharging current flows through diode rectifiers 324 and choke coil 328to recharge capacitors 320 and 322, an additional increment of charge isapplied to capacitor 325. Thus, capacitor 325 stores a quantity of equalcharges thereon, the quantity being equal to the number of pulses fromthe tachometer generator or other pulse generator, which, in turn, is afunction of the speed 0 the moving material.

When the voltage on capacitor 325 reaches a predetermined value due tothe accumulation of incremental charges thereon as just explained, thepredetermined voltage value required also depending upon the voltagedrop across resistors 338 and 339 as described in connection with theembodiment of FIG. 5, neon bulb 336 in series with the input to controlgrid 334 of the thyratron tube 329 will fire. The firing of neon bulb336 applies a pulse to the control grid of tube 328 which causesthyratron tube 328 to fire to actuate the output relay in the anodecircuit of tube 328 to control the clamping and cutting operations inthe same manner as previously described in connection with the otherembodiments of the invention.

With the S and D switches positioned in the same relative positions asin the diagrams of FIGS. 3 and 4, corresponding to a cutting of the pipeinto two equal lengths, the S switch will be actuated to open the Scontact through the S relay when the leading end of the pipe to be cutpasses adjacent the S switch. The S contact will remain open as long asthe pipe is passing adjacent the S switch. Opening of the S contactpermits capacitor 325 to become charged, as explained in connection withthe previous embodiments, although in the circuit of FIG. 8, thecapacitor 325 is not charged through limiting resistors as in theprevious embodiments, but rather is charge by a succession of equalincremental pulses as previously explained.

When the pipe to be cut projects rearwardly of the D switch, as shown inFIG. 4, the D switch is actuated to open contact D' through the D relay,to cause both capaci tors 320 and 322 to be connected in series. Withboth capacitors 320 and 322 connected in series with each other, thetotal capacitance of the two series-connected capacitors in one-halfwhat it would be with only one of these two identical capacitors in thecircuit, with the result that the recharging pulses to capacitors 320322are each only half as large as they would be if only capacitor 320 werein the circuit. Hence, the rate of charging of capacitor 325, which iscontrolled by the recharging pulses to capacitors 320-322, is onlyone-half what it would be if only capacitor 320 were in circuit.

When the pipe passes the D switch, the D contact is closed by the Drelay to bypass capacitor 322, with the result that only capacitor 320is in circuit. This causes the charging rate of capacitor 325 to doubleas compared to the rate when both capacitors 320 and 322 were incircuit, causing timing capacitor 325 to charge up to a predeterminedvoltage twice as fast as previously.

Thus, the action of the D contact and its bypassing relation tocapacitor 322 to permit doubling the charging rate to capacitor 325 whencapacitor 322 is shunted by the D contact provides the same type oftiming action to cause the cut to the made exactly at the midpoint ofthe pipe, as that described in connection with the constant speed timingcircuits of FIGS. 2 and 5, in which resistors were used instead ofcapacitors to control the charging rate on the timing capacitor whichaccumulates charges to trigger the firing of the thyratron tube. Thevariable speed timing circuit of FIG. 8 additionally compensates for thevariable rate of speed of the moving material by controlling thefrequency of the pulses to capacitors 320 and 322 and hence determinesthe rate of increase of the charge on the timing capacitor 325.

The timing circuit shown in FIG. 8 is very flexible in its operation andthe variable capacitors 320322 may be adjusted so that the total numberof pulses required to raise timing capacitor 325 to the trigger voltagemay vary over a wide range, as, for example, from one pulse to severalthousand pulses. The unit is capable of responding to an input pulserate from a pulse source over a wide range of frequncies, such as therange of four pulses per minute to 100 pulses per second. The pulsesreceived by the timing circuit may be of any wave form or shape from awave shape having a smooth slow rise and fall to a sharp spiked pulsewith a duration as short as one millisecond or less. In an operationalembodiment, the pulses feed into an impedance of 50K ohms and can be ofany voltage from a minimum of 2 volts to a maximum of 100 volts withoutseries resistance being added. Resistance of the order of 10K ohms pervolt for the lowest pulse voltage expected may be added in series withthe pulse source and will not change the counting accuracy but willrelieve the internal pulse circuit of unnecessary strain.

Since the pulses feeding the timing circuit of FIG. 8 may be of a widevariety of voltages and wave shapes without causing an error in thecount, almost any type of pulse generator may be used, including thesimple A.C. tachometer generator previously referred to. The pulsesource may also include pulses or light or radiation from a hot movingobject which could be picked up by 21 variable resistance device such asa phtototube or a silicon photodiode to supply pulses indicative of therate of movement of the moving material.

The variable speed timer can measure accurately for cutting a pipe ofknown or unknown length traveling at a varying speed, even a pipe whichis stopping and restarting.

By adjusting the capacitance value of the adjustable capacitor 322relative to capacitor 320, the change in pulse value when contact D isclosed compared to the pulse value when it is open may be used to adjustthe apparatus for different fractional cuts, as, for example, theone-third cut described in the embodiment of FIGS. 6 and 7. Thismodification would also involve a placement of the S and D switches inpositions similar to those shown in FIG. 7.

Any of the timing devices hereinbefore described may be used to cut apredetermined fixed length of pipe rather than a predeterminedfractional length of pipe. This may be done by eliminating ordisconnecting the D switch and the contacts controlled thereby and usingonly the S switch which is first actuated by movement adjacent theretoof the leading end of the pipe. In such case, the circuit constants,whether they be the resistor sections of FIGS. 2, 5, and 6, or thecapacitors of the variable speed embodiment of FIG. 8, are so adjustedwith respect to the timing capacitor and are so correlated with respectto the speed of movement of the pipe and the characteristics of thethyratron tube, as to cause the thyratron tube to fire when apredetermined fixed length of pipe has passed by the S switch and by thecutter.

In any of the various embodiments described for cutting predeterminedfractional lengths, such as cutting a pipe into two equal lengths orthree equal lengths, the timing and control circuit will always operatein such manner as to cut at least one usable fractional length out of agiven length of pipe, even though the total pipe length before cuttingis insufficient to cut into the total number of fractional parts. Thus,for example, in the embodiment of FIGS. 25, in which the pipe is cutinto two equal lengths, assume that a pipe moves along the conveyorrolls toward the pipe cutter which is too short in its total length tobe cut into two minimum 50-foot lengths. Thus, assume that a pipe feetlong moves along the conveyor rolls where the minimum length beforecutting for which the S and D switches are set is feet. It will be clearfrom the previous description given that the movement of the pipe pastthe S switch will start the timing circuit in operation in such manneras to cause a cut to be made at the end of 50 feet of movement of the80-foot pipe, leaving a piece remaining which is 30 feet in length. Thisis an improvement over prior art apparatus in which pipe having a lengthbefore cutting less than the required minimum length is sometimes cutinto two equal lengths, each of which is shorter than the requiredminimum length after cutting.

Similarly, in the case of the embodiment of FIGS. 6 and 7, where thetiming device functions to cut a pipe length into three equal lengths,assume that a pipe having a length of less 100 feet moves toward thecutter. It will be clear from the description previously given that thetiming and control system of FIGS. 6 and 7 will operate first to cut apiece equal to the minimum one-third fractional length, namely, asection 33 /3 feet in length, during the first of the two separatemeasuring and cutting operations previously described in connection withthe embodiment of FIGS. 5 and 6. The timing circuit will then switchover to its connections for the second step, in which the length of thepipe remaining after the first one-third cut has been made is cut, toprovide a second minimum one-third fractional length, if the pipe issufiiciently long to permit two such cuts to be made. Thus, out of thetotal length of pipe, at least one, and possibly two, useful one-thirdlength sections will be provided, depending upon the length of the pipe.

Reference is now made to FIGS. 9-12 which relate to the apparatus andtiming circuitry used to crop predetermined lengths from the forwardends of longitudinally moving material to eliminate off-gauge, rough, orirregular ends.

As seen in FIG. 9, which shows schematically the orientation of thesensing switches used in connection with the cropping operation, a pairof switches A and B are spaced apart from each other along the path ofmovement of the pipe or the like which is to be cropped. Switch A ispositioned to be reached first by the forward end of the movingmaterial, and switch B is positioned following switch A so as to bereached later by the forward end of the moving member. A cutting memberC is positioned beyond switch B along the path of the moving material.The switches A and B may be displaced any predetermined distance fromeach other along the path of movement of the moving material, and in theillustrated embodiment it is assumed that they are displaced ten feetfrom each other. Similarly, the cutter C may be displaced anypredetermined distance beyond the switch B, and in the illustratedembodiment it is assumed that cutter C is displaced ten feet beyondswitch B. The A and B switches are preferably switches of the proximitytype which do not require actual contact with the moving material.Proximity switches are well known in the art and may operate either onthe inductive or capacitive principle. The A sensing switch whenactuated to closed position by the presence of the forwardly movingmaterial energizes the operating coil of the A relay to actuate normallyopen contact A-l to closed position and to actuate normally closedcontact A2 to open position, as will be further explained hereinafter.The B sensing switch when actuated to closed position by the presence ofthe forwardly moving material energizes the operating coil of the Brelay to actuate normally open contacts B-l, B-3, and B4 to closedposition and to actuate normally closed contact B-2 to open position, aswill be further explained hereinafter.

Referring now to FIG. 10, the timing circuit for the cropping operationderives its input power from an alternating current supply connected tothe primary winding 402 of a transformer generally indicated at 400. Thesecondary winding 404 of transformer 400 is connected to a voltagedoubling circuit including capacitors 406 and 408 and diode rectifiers410 and 412. The voltage doubling circuit also includes resistors 414and 416. The DC. output of the voltage doubling circuit is applied to avoltage regulator generally indicated at 418, formed by a plurality ofseriesaconnected neon tubes.

The timing circuit includes a storage capacitor 420 having a terminal422 which is directly connected by conductor 424 to the midpoint 426 ofthe bank of neon tubes which form voltage regulator 418. The oppositeterminal 428 of capacitor 420 is connected to the negative terminal ofthe voltage regulator 418 in series with resistor 430, normally opencontact Al operated by the A relay through the A switch, and in serieswith the normally closed contact B2 operated by the B relay throughactuation of the B sensing switch. Terminal 428 of capacitor 420 is alsoconnected to the positive side of the voltage regulator 418 in serieswith fixed resistor 436 and variable resistor 438, and in series withnormally open contact B1 which is operated to closed position byenergization of the B relay through closure of the B sensing switch.

The A relay, when energized, also opens normally closed contact A2 whichis connected in parallel shunting relation with storage capacitor 420 sothat when contact A2 is closed capacitor 420 does not charge, but whencontact A2 is open capacitor 420 is permitted to charge.

The timing circuit of FIG. also includes a thyratron gaseous dischargetube generally indicated at 450, having an anode 452, a cathode 454, acontrol grid 456, and a screen grid 458 which is grounded to cathode454.

The anode 452 of tube 450 derives its DC. voltage supply from a voltagedoubler circuit supplied from secondary winding 474 of a transformergenerally indicated at 470, whose primary winding 472 is connected tosecondary winding 476 of transformer 400. The voltage doubler circuitincludes capacitors 478 and 480 and diode rectifiers 482 and 484. Theoutput of the voltage doubler circuit is applied in series with aresistor 486 across a pair of series-connected Zener diodes 488 and 490which maintain a stable regulated D.C. voltage output. Anode 452 andcathode 454 are connected across Zener diode 490 to maintain a stableanode supply voltage. Control grid 456 is supplied with a negative biasby the adjustable resistor 492 connected across Zener diode 488,resistor 492 including an adjusting tap 494 connected to control grid456 in series with capacitor 420.

An output relay generally indicated at 460 is connected in the circuitof anode 452, relay 460 including an operating coil 462 which, whenenergized, controls the closure of contacts 464 and 466 which arerespectively in the cutter and clamping circuits used to cut and clampthe moving workpiece as in the previous embodiments of the invention.

The timing circuit also includes a reset relay RR having an operatingcoil which is energized when contact 468 is closed by the operation ofoutput relay 460 which will be explained more fully hereinafter. Whenreset relay RR is energized, it opens normally closed contact R-1 inseries with the anode circuit of tube 450. Opening of contact R-ldisconnects the voltage supply from anode 452 thereby to extinguish thetube and give control back to control grid 456, as is well known inconnection with thyratron gas tubes.

In order to insure against firing of the tube 450 during furthermovement of the member which has just been cropped, a holding circuit isprovided to keep reset relay RR energized until the trailing end of themoving pipe or the like has passed the B switch. The holding circuitincludes a contact R2, which is closed upon energization of relay RR, inseries with normally open contact B-4. Contact B4 is further in serieswith contact R-2 and is closed by actuation of the B relay due to thepassage of the moving material past the B switch. Contact. B4 isnecessarily already closed at the time reset relay RR is energized bythe momentary closing of contact 468 when the timers output relay 460operates to give control to crop out, so the relay holding circuit iscompleted and does not reopen until the trailing end of the pipe hasmoved past the B switch. Thus, it is impossible for another cuttingoperation to occur on the moving pipe after the cropping out has beenmade.

Operation oftiming circuit of FIG. 10

It will be assumed that the sensing switches A and B are positioned tenfeet from each other along the path of movement of the moving material,and that the cutter C is positioned ten feet beyond switch B, all asshown in FIG. 9. Assume also that it is desired to crop a length of 2.5feet from the forward end of each piece of moving material which movespast the sensing switches A and B and the cutter C.

It is also assumed that thyratron gas tube 450 has a characteristic suchthat at the given supply voltage on anode 452, tube 450 will not firewhen the bias on control justed to maintain a grid bias voltage justequal to the trigger voltage.

With the placement of the sensing switches and cutter as shown in thediagram of FIG. 9, the charging period of the capacitor 420 is duringthe interval in which the forward end of the moving material moves fromsensing switch A to sensing switch B, a distance of ten feet, while thedischarging period of the capacitor is the time interval required forthe forward end of the advancing material to move from sensing switch Bto cutter C, a distance of ten feet, plus the desired length of crop,which, in the assumed example, is 2.5 feet. Thus, in the example, theinterval for discharge of capacitor 220 is the time interval requiredfor the forward end of the advancing material to move a total distanceof 12.5 feet. Therefore, the ratio of the charging interval tothedischarging interval is 0.8, and the ratio of the rate of dischargeto the rate of charge must be 0.8 for the total discharge toquantitatively When the forward end of the material which is to becropped reaches the A switch, the A switch closes to energize the Arelay. Energization of the operating coil of the A relay opens thenormally closed shunting A2 to permit capacitor 420 to charge.Energization of the A relay also closes the normally open contact A-l toconnect terminal 428 of capacitor 420 to the negative terminal ofvoltage regulator 418, in series with resistor 430, in series withcontact A-1, and in series with normally closed contact B-2 controlledby the B relay.

Terminal 428 of capacitor 420 continues to be connected to the negativeterminal of voltage regulator 418 as just described during the intervalrequired for the forward end of the advancing material to pass throughthe space from sensing switch A to sensing switch B, a distance of tenfeet in the illustrated embodiment of FIG. 9. During this interval,capacitor 420 becomes progressively more negatively charged, asindicated, for example, by the graphs of FIGS. and 11, which illustratecharging and discharging with different constants for the timing circuitthan in this example but indicate the principle involved. The negativecharge of capacitor 420 adds to the negative bias of approximately voltsestablished by the biasing resistor 492 to maintain control grid 456 ofthyratron tube 450 at a negative value such that tube 450 cannot fire.Furthermore, during the charging interval when only relay A is closed,contact B-3 in the anode circuit of tube 450 and controlled by the Brelay is in its normally open position, so that tube 450 cannot fireduring the interval in which the forward end of the advancing materialmoves from sensing switch A to sensing switch B.

When the forward end of the advancing material reaches sensing switch B,the B switch is closed to energize the operating coil of the B relay, toclose the normally open contact B-l in the discharge circuit for thecapacitor and to open the normally closed contact 13-2 in the chargingcircuit for capacitor 420. Thus, terminal 428 of capacitor 420 isconnected through closed contact B-1 and resistor sections 436 and 438to the positive terminal of voltage regulator 418, so that capacitor 420begins to discharge, the discharge rate in the assumed example being 0.8of the charging rate as determined by the adjustment of variableresistor 438. Closure of the B switch and energization of the operatingcoil of relay B also is effective to close the normally open contact B-3in the circuit of anode 452 of thyratron tube 450. When capacitor 420becomes completely discharged and reaches a zero voltage after a timeinterval determined by the timing circuit constant of 0.8, the negativepotential on control grid 456 is then determined only by the negativebias established by bias resistor 492 which, as previously stated, isset to equal the trigger voltage of thyratron tube 450. At this instant,tube 450 fires to energize output relay 460 in the output circuit ofanode 452. Energization of the operating coil 462 of relay 460 actuatescontacts 464 and 466 in the cutter and clamp circuits to clamp themoving material and to actuate the cutter to make the cropping cut onthe material which has been clamped in position. Assume, in theforegoing example, that the material to be cropped passes from sensingswitch A to sensing switch B in ten seconds, moving at a constant rateof one foot per second, and that the constant for the timing circuit hasbeen set at 0.8 as just described. The material will travel for 12.5seconds after reaching the B switch before the capacitor 420 completelydischarges to zero voltage across the capacitor, leaving only thetrigger voltage provided by bias resistor 492 on control grid 456. Atthe constant rate of movement of one foot per second assumed in theexample, the forward end of the moving material will project 2.5 feetbeyond the cutter C at the time the thyratron tube 450 fires to actuatethe clamping and cutting means, so that a length of 2.5 feet will becropped from the forward end of the moving material.

With a given constant for the timing circuit, such as the constant 0.8just described, the same length of material will be cropped from theforwardly moving end of the material regardless of the speed of theadvancing material as long as the speed, whatever it may be, remainsconstant. Thus, for example, with the constant of the timer set at 0.8as described in the previous example, assume that the speed of themoving material is increased so that only two seconds are required forthe forward end of the material to move the ten foot distance fromsensing switch A to sensing switch B. Thus, the capacitor 420 would becharged during an interval of two seconds. When the end of the materialreaches sensing switch B and disconnects the charging circuit andconnects the discharge circuit, a period of 2.5 seconds will elapsebefore the capacitor 420 discharges back to the zero voltage level atwhich the charging period began, at which the negative bias on negativegrid 456 is only that provided by biasing resistor 492, namely, the 2.5volts equal to the trigger voltage of tube 450. During this 2.5 secondinterval of the discharge of of capacitor 420, the forward end of themoving material would have moved 12.5 feet beyond sensing switch B atits now assumed rate of 5 feet per second. This would place the forwardend of the material 2.5 feet beyond the cutter C when the tube fires,and thus 2.5 feet would again be cropped from the forward end of thematerial, as in the preceding example, in which the material was assumedto be moving at only one foot per second. Thus, with a given constantsetting of the timing circuit, the same length of cropping cut will bemade regardless of the speed of movement of the material, as long as thespeed of movement is constant.

Actuation of output relay 460 serves to close contacts 464, 466 and 468,thereby energizing the cutting, clamping, and reset relay RR circuits. Asuitable holding circuit may be provided so that these circuits willremain energized throughout the complete holding and cutting operation.The holding circuit will necessarily be deenergized when the cutter isretracted to the initial or non-cutting position while the clamp ismoved to the unclamped position. Suitable, means, such as a limitswitch, may be provided to insure that when the clamp and cutter aredeenergized they will be prepared for the next cutting cycle.Energization of reset relay RR opens contact R-l in the circuit of anode452 of thyratron tube 450 to interrupt thereby the firing of the tubeand deactivate the tube until the next cycle of operation. Thedeenergization of tube 450 deenergizes operating coil 462 of the outputrelay and causes contacts 464 and 466 to move to deactivated positions.Since the operation of output relay 460 closes contact 468, energizingreset relay RR, and reset re'lay contact R-l opens to deenergize outputrelay 460, output relay contacts 464 and 466 would stay closed for avery short period of time. A series connected capacitor 520 and resistor522 are connected in shunt with series connected contacts B-3 and R-1.When reset relay contact R-1 opens to deenergize output relay 460, thecharging current taken by capacitor 520 will be suflicient to keepoutput relay 460 energized for the necessary length of time sufficientto hold output relay contacts 464 and 466 closed long enough to startthe cutting and clamping cycle. As hereinbefore pointed out, each of theclamping and cutting circuits is provided with a suitable holdingcircuit to insure the clamping and cutting cycle is completed beforedeenergization occurs.

The reset relay RR remains energized to hold contact R-l in the circuitof anode 452 open until the trailing end of the moving material hasmoved past the B switch, thereby to insure that no additional cuts aremade after the cropping cut. This is accomplished by the holding circuitfor relay RR, including the contact R-2 closed by relay RR, and contactB-4 which is held closed by the B relay as long as the B relay isenergized by the passage of the workpiece past the B switch. A voltagebuildup at the grid 456 of the thyratron 450 is prevented by theenergization of reset relay RR which closes contact R-3 in shuntingrelationship to capacitor 420. I

During the passage of the remaining portion of the member which has justbeen cropped, both the A and B switches remain closed due to theproximity of the passing material, and the A and B relays remainenergized as long as the material continues to pass by the A and Bswitches.

As soon as the trailing end of the material has passed the A switch, theA switch opens to deenergize the A relay thereby to reclose normallyclosed contact A4 of the A relay which shunts capacitor 420. As soon asthe trailing end'of the material passes the B switch, the B switch opensto deenergize the operating coil of the B relay, thereby to opennormally open contact B-l in the discharge circuit and to permitnormally closed contact B4 in the charging circuit to reclose. Also,deenergization of the B relay opens normally open contact B3 in theoutput circuit of anode 452 of tube 450 and opens normally open contactB-4 in the holding circuit for reset relay RR thereby to deenergize theoperating coil of the reset relay and permit normally closed resetcontact R-1 in the circuit of anode 452 to reclose. Normally opencontact R-3, which is closed shunting capacitor 420, is opened when thereset relay RR is deenergized. Thus, when the end of the passingmaterial has moved past the A and B switches, the circuit is restored tothe condition in which it is ready to crop the next piece of movingmaterial which approaches the A and B switches.

It can be seen from the foregoing that there is provided, in accordancewith this invention, an electronic timing and cutting apparatus andmethod which have great utility, particularly in connection with cuttingof moving material, such as pipes, rods, extrusions, and the like intopredetermined fractional lengths or into predetermined fixed lengths, orfor cropping predetermined lengths from the ends of moving material.

The apparatus of the invention does not require a high initialinvestment, as in the case of most prior art apparatus for the samepurpose, and presents very little in the way of maintenance problems.The apparatus can be used for either cutting moving material intopredetermined fractional lengths or into repeating fixed lengths, asrequired. The timing and control apparatus are efficient anduncomplicated in their operation and permit the use of relatively simplecontrols for adjusting the apparatus for varying operating conditions.The timing and cutting apparatus also insures that when the movingmaterial is less than the minimum length required to provide a pluralityof cuts of minimum length, the material will be cut in such manner as toprovide one or more usable fractional lengths, rather than a pluralityof fractional lengths, none of which is equal to the minimum lengthrequired. Also, the timing and control apparatus illustrated inconnection with FIGS. 912 provides a very effective and efficient meansfor cropping predetermined lengths from the ends of pipes, rods,extrusions and the like, where it is necessary to make cropping cuts onsuch members.

While there have been shown and described particular embodiments of theinvention, it will be apparent to those skilled in the art that variouschanges and modifications may be made therein without departing from thespirit of the invention and, therefore, it is aimed to cover all suchchanges and modifications as fall Within the true spirit and scope ofthe invention.

I claim:

1. A timing circuit to control the cropping of predetermined variablelengths from the end of a longitudinal member moving along a transportpath, comprising: a first sensing means positioned along a transportpath and generating an output signal in response to the leading end ofsaid moving material passing thereby, a second sensing means positionedalong the transport path posteriorly of the first sensing means withrespect to the direction of material travel and generating a signal inresponse to the leading end of said moving material passing thereby, agaseous discharge device biased in a normal cut-off condition and havinginput and output circuits, a timing condenser operatively connected tosaid input circuit of said gaseous discharge device for control thereof,a timing condenser charging path including normally open contactscontrolled by said first sensing means and normally closed contactscontrolled by said second sensing means, said timing condenser chargingpath accordingly being operative to charge said timing condenser uponthe leading end of an item passing by said first sensing means, acondenser discharge path including a normally open contact controlled bysaid second sensing means, said condenser discharge path being operableto discharge said timing condenser to a triggering level for saidgaseous discharge in response to the leading end of an item passing bysaid second sensing means, said condenser discharge path having adifferentially variable amount of impedance therein to enable thetriggering of said gaseous discharge device upon said moving materialassuming a predetermined position in said transport path, materialclamping means operatively positioned along the path of material traveland responsive to energization of said gaseous discharge device torestrain said material and prevent further movement along said transportpath, material cutting means operatively positioned along the materialtransport path such that upon energization of said gaseous dischargedevice the predetermined desired amount of leading end will have passedthereby, gaseous discharge device resetting means operative in responseto energization of said cutter means to remove the operating potentialtherefrom, clamping and cutting hold circuit means insuring properduration of said clamping and cutting operation after dcenergization ofsaid gaseous discharge device by said re setting means, said resettingmeans being operable for as long as said moving material is sensed bysaid second signal generating means.

2. For use with a material clamping and cutting apparatus which iscontrolled by a normally nonconducting gaseous discharge device which isresponsive to a triggering voltage applied to the input circuit thereoffor actuation of said material clamping and cutting operation, a timingcircuit to control the cropping of predetermined variable lengths fromthe end of a longitudinal member moving along a transport path,comprising, a first sensing means positioned along a transport path andgenerating an output signal in response to the leading end of saidmoving material passing thereby, a second sensing means positioned alongthe transport path posteriorly of the first sensing means with respectto the direction of material travel and generating a signal in responseto the leading end of said moving material passing thereby, a timingcondenser operatively connected to the input circuit of the gaseousdischarge device for control thereof, a timing condenser charging pathincluding normally open contacts controlled by said first sensing means,said timing condenser charging path accordingly being operative tocharge said timing condenser upon the leading end of an item passing bysaid first sensing means, a condenser discharge path including anormally open contact controlled by said second sensing means, saidcondenser discharge path being operable to discharge said timingcondenser to the triggering level of the gaseous discharge tube inresponse to the leading end of an item passing by said second sensingmeans, said condenser discharge path having a differentially variableamount of impedance therein to enable the triggering of said gaseousdischarge device upon said moving material assuming a predeterminedposition in said transport path relative to the,cutting apparatus,deenergization means for the gaseous discharge device operative inresponse to energization of said cutter means to remove operatingpotential therefrom, clamping and cutting hold circuit means insuringproper duration of said clamping and cutting operation afterdeenergization of said gaseous discharge devlce.

3. A circuit for cropping predetermined variable amounts of leading endsfrom a longitudinal member moving along a transport path and thereafterpreventing further cutting operations from occurring thereupon thecombination comprising, a first sensing means positioned along atransport path and generating an output signal in response to theleading end of said moving member passing thereby, a second sensingmeans positioned along the transport path posteriorly of the firstsensing means with respect to the direction of material travel andgenerating a signal in response to the leading end of said movingmaterial passing thereby, a gaseous discharge device having input andoutput circuits, means operatively connected to the input circuit ofsaid gaseous discharge device and biasing said gaseous discharge devicein a normally cutoff condition, a timing condenser operatively connectedto the input circuit of said gaseous discharge device for controlthereof, a timing condenser charging path including first normallyopened contacts controlled by said first sensing means and firstnormally closed contacts controlled by said second sensing means, saidtiming condenser charging path operative to charge said timing condenserto a predetermined gaseous discharge device cut-off level upon theleading end of said member assuming a position along said transport pathbetween said first and second sensing means, a condenser discharge pathincluding a second normally opened contact controlled by said secondsensing means, said condenser discharge path operable to discharge saidtiming condenser to the triggering of said gaseous discharge device inresponse to the leading end of said member being sensed by said secondsensing means, said condenser discharge path having a differentiallyvariable amount of impedance therein settable to enable triggering ofsaid gaseous discharge device upon said longitudinally moving memberassuming a predetermined position in said transport path, memberclamping means operatively positioned along the path of member travelrestraining said member and preventing further movement along saidtransport path, member cropping means operatively positioned along saidtransport path posteriorly of said first and second sensing means, inthe direction of member movement, such that upon energization of saidgaseous discharge device a predetermined desired amount of leading endwill have passed thereby, means connected in said output circuit of saidgaseous discharge device for initiation of said clamping and croppingmeans in response to energization of said gaseous discharge device,gaseous discharge device resetting means including second normallyclosed relay contacts controlled thereby, operative in response to theoccurrence of a cropping operation, said second normally closed relaycontacts controlled by said resetting means operatively connected inseries circuit with said clamping and cropping initiation means in saidoutput circuit of said gaseous discharge device, such that uponenergization of said gaseous discharge device said cutting and clampingmeans are operative, said gaseous discharge reset-ting means opera tivein response to performance of said cropping operation to open itsassociated second normally closed relay contacts connected in saidoutput circuit of said gaseous discharge device to de-energize saidgaseous discharge device, and a gaseous discharge device resetting meansholding circuit including a third pair of normally opened relay contactscontrolled by said second sensing means to prevent further energizationof said gaseous discharge device for as long as said second sensingmeans is responsive to said member passing thereby along the transportpath.

4. A combination as described in claim 3 including a clamping andcutting hold circuit means insuring proper duration of said clamping andcutting operation after deenergization of said gaseous discharge deviceby said resetting means.

5. A combination as described in claim 4 wherein said clamping andcutting hold circuit is connected in parallel with said second normallyclosed relay contacts controlled by said gaseous discharge deviceresetting means in said output circuit of said gaseous discharge device.

6. A combination as described in claim 5 wherein said clamping andcutting hold circuit includes a serially connected resistance andcondenser timing circuit having a predetermined discharge rate to insureproper duration of the cutting and clamping operations after ade-energization of said gaseous discharge device occurs.

References Cited by the Examiner UNITED STATES PATENTS 2,473,640 6/49Faulk 324-68 X 2,655,994 10/53 Vandenberg 83-365 X 2,898,995 8/59Funnell 832l0 WILLIAM W. DYER, JR., Primary Examiner.

LEON PEAR, ANDREW R. JUHASZ, Examiners.

1. A TIMING CIRCUIT TO CONTROL THE CROPPING OF PREDETERMINED VARIABLELENGTHS FROM THE END OF A LONGITUDINAL MEMBER MOVING ALONG A TRANSPORTPATH, COMPRISING: A FIRST SENSING MEANS POSITIONED ALONG A TRANSPORTPATH AND GENERATING AN OUTPUT SIGNAL IN RESPONSE TO THE LEADING END OFSAID MOVING MATERIAL PASSING THEREBY, A SECOND SENSING MEANS POSITIONEDALONG THE TRANSPORT PATH POSTERIORLY OF THE FIRST SENSING MEANS WITHRESPECT TO THE DIRECTION OF MATERIAL TRAVEL AND GENERATING A SIGNAL INRESPONSE TO THE LEADING END OF SAID MOVING MATERIAL PASSING THROUGH, AGASEOUS DISCHARGE DEVICE BIASED IN A NORMAL CUT-OFF CONDITION AND HAVINGINPUT AND OUTPUT CIRCUITS, A TIMING CONDENSER OPERATIVELY CONNECTED TOSAID INPUT CIRCUIT OF SAID GASEOUS DISCHARGE DEVICE FOR CONTROL THEREOF,A TIMING CONDENSER CHARGING PATH INCLUDING NORMALLY OPEN CONTACTSCONTROLLED BY SAID FIRST SENSING MEANS AND NORMALLY CLOSED CONTACTSCONTROLLED BY SAID SECOND SENSING MEANS, SAID TIMING CONDENSER CHARGINGPATH ACCORDINGLY BEING OPERATIVE TO CHARGE SAID TIMING CONDENSER UPONTHE LEADING END OF AN ITEM PASSING BY SAID FIRST SENSING MEANS, ACONDENSER DISCHARGE PATH INCLUDING A NORMALLY OPEN CONTACT CONTROLLED BYSAID SECOND SENSING MEANS, SAID CONDENSER DISCHARGE PATH BEING OPERABLETO DISCHARGE SAID TIMING CONDENSER TO A TRIGGERING LEVEL FOR SAIDGASEOUS DISCHARGE IN RESPONSE TO THE LEADING END OF AN ITEM PASSING BYSAID SECOND SENSING MEANS, SAID CONDENSER DISCHARGE PATH HAVING ADIFFERENTIALLY VARIABLE AMOUNT OF IMPEDANCE THEREIN TO ENABLE THETRIGGERING OF SAID GASEOUS DISCHARGE DEVICE UPON SAID MOVING MATERIALASSUMIGN A PREDETERMINED POSITION IN SAID TRANSPORT PATH, MATERIALCLAMPING MEANS OPERATIVELY POSITIONED ALONG THE PATH OF MATERIAL TRAVELAND RESPONSIVE TO ENERGIZATION OF SAID GASEOUS DISCHARGE DEVICE TORESTRAIN SAID MATERIAL AND PREVENT FURTHER MOVEMENT ALONG SAID TRANSPORTPATH, MATERIAL CUTTING MEANS OPERATIVELY POSITIONED ALONG THE MATERIALTRANSPORT PATH SUCH THAT UPON ENERGIZATION OF SAID GASEOUS DISCHARGEDEVICE THE PREDETERMINED DESIRED AMOUNT OF LEADING END WILL HAVE PASSEDTHEREBY, GASEOUS DISCHARGE DEVICE RESETTING MEANS OPERATIVE IN RESPONSETO ENERGIZATION OF SAID CUTTER MEANS TO REMOVE THE OPERATING POTENTIALTHEREFROM, CLAMPING AND CUTTING HOLD CIRCUIT MEANS INSURING PROPERDURATION OF SAID CLAMPING AND CUTTING OPERATION AFTER DEENERGIZATION OFSAID GASEOUS DISCHARGE DEVICE BY SAID RESETTING MEANS, SAID RESETTINGMEANS BEING OPERABLE FOR AS LONG AS SAID MOVING MATERIAL IS SENSED BYSAID SECOND SIGNAL GENERATING MEANS.